Zebra mussels were first discovered in American waters in Lake St. Clair in 1988, ["Infestation of the Monroe Power Plant by the Zebra Mussel (Dreissena Polymorpha)", Kovalack, W. P., Longton, G. D., Smithee, R. D., Proceedings of the American Power Conference, Chicago, Ill., 1990]. It is believed that the mussel larvae were dumped into the water with a European or Western Asian ship's ballast water in 1985. The mussels have spread quickly throughout the Great Lakes Basin and are reasonably expected to infest waterways in most of the United States including Florida but excluding most of the other Southern and Southwestern states and to infest most of southern Canada. They have spread throughout most of Europe with the exception of northern Scandinavia, the Iberian Peninsula and Italy. They are also in western Asia where they originally inhabited the Ural River and Caspian Sea but now cover almost all of Russia, extending into Turkey ["Impact of the European Zebra Mussel Infestation to the Electric Power Inudstry", McMahon, R. F., Tsou, J. L., Proceedings of the American Power Conference, Chicago, Ill., 1990].
Zebra mussels float through the waters in a free swimming planktonic veliger state. They attach to any hard surface with byssal threads. The byssus contains up to 200 threads which are difficult to remove from a surface even after death. They may attach to other mussel shells and form large clumps of mussels which threaten to block intake lines of raw water supplying power plants and municipal water authorities ["Control of Zebra Mussels at CEI Facilities", Barton, L. K., Proceedings of the American Power Conference, Chicago, Ill., 1990].
Workers in the art have attempted to control macroinvertebrates generally by dissolving into the environment of the target organisms various amines and/or quaternaries. See, for example, U.S. Pat. No. 4,816,163 to Lyons et al, U.S Pat. No. 4,857,209 to Lyons et al, U.S. Pat. No. 4,906,385 to Lyons et al, U.S. Pat. No. 4,970,239 to Whitekettle et al, and U.S. Pat. No. 4,579,665 to Davis et al. When zebra mussels received attention, they also were attacked through the use of various water-soluble materials, such as the halides of Ekis, Jr. et al U.S. Pat. No. 5,141,754, the particular quaternary ammonium compounds of Gill in U.S. Pat. No. 5,128,050, and Muia et al in U.S. Pat. No. 5,062,967, and the quaternary ammonium polymers of Muia et al in U.S. Pat. Nos. 5,015,39 and 5,096,601. Bollyky et al in U.S. Pat. No. 5,040,487 use ozone. All such approaches are to treat the aqueous environment in which the zebra mussels live.
Generally, the environments treated are open to circulation of water, and accordingly, the maintenance of an effective concentration of such materials requires continuous or frequent feeding, which means a risk must be calculated as to the tolerance of other living things in the environment for the materials introduced, even if the effective concentrations to be maintained are relatively low.